Instrumental contributions to band broadening in gas chromatography

Cram, Stuart P.; Glenn, Tom H.

doi:10.1016/s0021-9673(00)99965-5

Cited by 18 publications

(8 citation statements)

References 37 publications

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“…Column efficiency and resolution ultimately depend upon physicochemical column processes to achieve a differential rate of migration and to minimize solute band broadening (346). Column retention mechanisms, therefore, were investigated under conditions of nonlinearity, sorption, finite inlet band width, mobile phase nonequilibrium, gas phase compressibility (378), and eluent steric and structural factors (1357, 1623).…”

Section: Columnsmentioning

confidence: 99%

“…Chesler and Cram (292) developed an iterative curve fitting method for deconvoluting intrinsic peak shape characteristics and for statistical moment analysis. Statistical moments are now widely used in GC to characterize column efficiencies ( I 703), instrumental contributions to band broadening (346), the influence of mass transfer phenomena and kinetic retention mechanisms (1636), linear equilibrium and nonequilibrium column processes (1705,1706,1708), the effects of nonlinearity of the distribution isotherm on solute retention and column efficiency via computer simulation (1707), adsorbents in GSC having a bidispersed structure (847), peak asymmetry (954), and the effects of particle size distributions on the pressure drop and chromatographic performance (1587). Moment vectors described the breakthrough curve for coupled columns ( 1 709).…”

Section: Columnsmentioning

confidence: 99%

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Gas chromatography

Cram¹,

Juvet²

1976

Anal. Chem.

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Section: Columnsmentioning

confidence: 99%

Section: Columnsmentioning

confidence: 99%

Gas chromatography

Cram¹,

Juvet²

1976

Anal. Chem.

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“…From peak skewness and excess, different extracolumn band broadening models (e.g. exponential dilution) can be checked and their characteristic parameters evaluated (6,9,13,16,17). In fact, the extracolumn effect variances are independent and additive (5,18,19)…”

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confidence: 99%

Fluidic and syringe injection study by peak shape analysis

Remelli¹,

Blo²,

Dondi³

et al. 1989

Anal. Chem.

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Fluidic and syringe injections with different splitting conditions are compared by using the Edgeworth-Cramer peak shape analysis. Non retained component peaks on capillary and packed columns were considered. Skewness values as low as 0.02, with precision and repeatability of ±0.005, were obtained when using the capillary column with fluidic injection. Extracolumn contributions coming from the injection system were evaluated by using peak skewness under the hypothesis of exponential decay extracolumn factor. The corrected column efficiency values are in good agreement with the theoretically expected van Deemter equation data. A syringe injection system with high split rate can produce, for unretained samples, peak fidelity values greater than 0.8, which are comparable with those observed with the fluidic injection system. Applications in column performance studies are discussed

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“…(IO), and instrumental inefficiency (11). These treatments do not attempt to simulate particular separations but result in requirements on those that do.…”

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confidence: 99%

“…Simulation of gas chromatographic behavior has been reported under three general approaches. Classical or semiclassical theoretical treatments (1-5) describe the dependence of separation efficiency of unspecified analytes on changes in column length (6,7) and cross-section (8, 9), carrier pressure (10), and instrumental inefficiency (11). These treatments do not attempt to simulate particular separations but result in requirements on those that do.…”

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confidence: 99%

Simulation of gas chromatographic retention and peak width using thermodynamic retention indexes

Dose¹

1987

Anal. Chem.

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The computational simulation of tsinperatursprogrammed gas Chromatographic behavlor of two serles of analytes Is Investigated. The approach presented accounts for both retention-time and peak-width behavlor over diverse temperature programs. The effect of the temperature dependence of carrier gas vlscoslty Is Included In the treatment. Sbnulatlon accuracies are generally 1 % for retention and 10-15 % for peak widths. The isothermal retention t h e data used as input of the simuiatlon are most conveniently reduced to two thennodynamlc quantltles AS, and AHv whkh are proposed as a new class of retention Indexes.Simulation of gas chromatographic behavior has been reported under three general approaches. Classical or semiclassical theoretical treatments (1-5) describe the dependence of separation efficiency of unspecified analytes on changes in column length (6, 7) and cross-section (8,9), carrier pressure (IO), and instrumental inefficiency (11). These treatments do not attempt to simulate particular separations but result in requirements on those that do. A second approach adjusts isothermal retention times (12)(13)(14) or retention indexes (15-23) for oven temperature changes, generally using semiempirical or linear extrapolative methods which predict retention behavior over a limited range of available conditions. The present work follows the third approach, the simulation, whether thermodynamic or empirical, of physical and chemical processes occurring in the instrument (24-31). This approach, while computationally demanding, should afford simulation of specific separation processes and their results over a very wide range of conditions. The degree of success of properly applied, thermodynamically based direct simulation reflects the accuracy of current chromatographic theory.In this work, isothermal data were used to perform temperature-programmed experiments off-line, that is, on a computer rather than on a chromatograph. The accuracy of this method for two classes of analytes is demonstrated. The degree of reproducibility allows relatively small effects such as carrier-gas-viscosity temperature dependence to be verified and included in the treatment. EXPERIMENTAL SECTIONApparatus. Chromatograms were obtained on two Hewlett-Packard 5890A gas chromatographs with electron-capture detection. Temperatures from the chromatographs' controllers were used directly. No corrections for heating lag time (28) were applied to this capillary system. Organochlorine pesticides (OCPs) were eluted from a 30-m, 0.32 mm i.d. DB-17 capillary column (J&W Scientific) of f i l m thickness 0.25 wm. Nitroaromatic (NA) analytes were eluted from a 30-m, 0.53 mm i.d. DB-210+ column (J&W) of film thickness 1.0 pm. Helium was used as carrier for all experiments.Procedures. Peak retention times were measured at the detector signal maximum as indicated by the Hewlett-Packard 3392A integrator. One-day retention time reproducibility was to 0.01 YO, multiday reproducibilities were to 0.05%, and multiday reproducibilities of retention time ratios...

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Instrumental contributions to band broadening in gas chromatography

Cited by 18 publications

References 37 publications

Gas chromatography

Gas chromatography

Fluidic and syringe injection study by peak shape analysis

Simulation of gas chromatographic retention and peak width using thermodynamic retention indexes

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